The chief executive and chairman of BP will face hostile questioning from Congress today after the oil company's efforts to co-operate with White House demands were marred by another public relations gaffe as the company's chairman referred to Gulf coast residents as "small people".

BP bosses agreed in full to the US government's demands after a four-hour meeting with Barack Obama, and agreed to suspend dividend payouts to shareholders until next year and to set up a $20bn fund over three years to meet clean-up costs and compensation claims following its catastrophic oil spill in the Gulf of Mexico.

But as he left the White House, BP's chairman Carl-Henric Svanberg provoked fresh irritation among the oil company's critics with a poorly worded apology to the American people. He pledged to repair the damage caused by the spill and to look after all the shrimpers, fishermen, tourist workers and property owners affected.

"We care about the small people," said Svanberg, a native Swedish speaker who was formerly the head of the telecoms company Ericsson. "I hear comments sometimes that large oil companies are greedy companies or don't care but that's not the case with BP. We care about the small people."

Svanberg's comment prompted criticism in the blogosphere and among locals in the region hit by the spill. Douglas Brinkley, a Gulf coast historian at Rice University, said it was another example of BP's insensitivity. "It's snotty and deeply condescending and it shows the kind of corporate arrogance that BP has been exuding ever since the Deepwater Horizon accident," Brinkley said.

The remark is likely to be one of many contentious topics raised in a Congressional hearing today at which Svanberg and BP's chief executive, Tony Hayward, will be questioned by 35 lawmakers about the catastrophic spill in the Gulf of Mexico. Experts say the pair would be well-advised to adopt a supine posture in a forum that often becomes theatrical.

"They've just got to sit there and take it," says Dan McGinn, a communications adviser at TMG Strategies who has coached business bosses for similar hearings. "They've got to express deep regret and genuine humility. Hayward needs to say he accepts responsibility, that this happened on his watch."

Trying to deflect any portion of blame onto other parties would only inflame political outrage, as would any public quibbling over cost of the clean-up. But the examination requires a tricky balancing. Svanberg and Hayward also need to look authoritative, in command of the situation, to avoid any further erosion of confidence among investors.

"I would tell him [Hayward] that this isn't about you – you're a prop," says McGinn. "The theatrics, the setup – if you're looking for deep substance, forget it. They'll just want to pummel and hit BP, to demonstrate to the public and to their districts that they're tough."

Carl Messineo, organiser of a "seize BP" campaign that argues for the company's assets to be ring-fenced, says he wants to see Svanberg and Hayward brought to book for their "lies" in grossly under-stating the size of the spill, which has exploded from early estimates of 5,000 barrels per day to as much as 60,000 daily: "I would like Hayward to explain to the people of the Gulf coast directly why they should not be able to feed their families this week, they shouldn't be able to make their rent payments."

BP's $20bn fund will start with a $3bn contribution in the third quarter of 2010, followed by $2bn in the final three months of the year, then $1.25bn each quarter until the total is reached. It will be administered by Ken Feinberg, an independent Washington lawyer who assessed claims following the 9/11 terrorist attacks. BP will also set aside $100m to pay the wages of workers on rival firm's oil rigs laid off by a six-month freeze on deepwater drilling.

To create the disaster fund, BP intends to sell $10bn of "upstream" oil exploration assets around the world and will cut back capital investment in its global operations this year from $20bn to $18bn. The company hinted that it could seek contributions from US contractors involved in the leaking well – including Anadarko, Halliburton, Transocean and Cameron – by saying it expected its partners to "meet their obligations".

When asked what BP had obtained as a quid pro quo, the company's chief financial officer, Byron Grote, expressed hope for an end to "rhetoric" that has damaged the firm's reputation and stock price: "What we've got out of it, we believe, is an opportunity, for the first time, to have a constructive dialogue with the president of the United States and the administration."